Organic solar cells show much promise as an alternative to silicon-based solar cells because of their light weight, potential for low-cost fabrication, and their mechanical flexibility. One goal for commercial viability of organic solar cells is to produce devices having power conversion efficiencies (PCEs) comparable to their silicon-based counterparts. Another goal is to produce devices that have long lifetimes. Despite the low PCEs and short lifetimes associated with early devices, recent cost-analysis studies suggest that organic solar cells could become competitive with other solar cell technologies if modules with PCE of 5% and a 5 year lifetime could be produced. Over the last decade, the power conversion efficiency (PCE) of small-area organic solar cells has improved from values around 3.5% up to 10.6%, making such solar cells a viable technology.
Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyethersulfone (PES), have been used for the demonstration of flexible organic solar cells. However, from a life-cycle perspective, these petroleum-based substrates are typically expensive and environmentally less attractive than easily recyclable or biodegradable substrates. A need exists for renewable and/or environmentally friendly materials for the realization of a sustainable solar cell technology.